Integrated LED FPCB for LCD Backlight Connection Reliability
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Solution Overview
Problem
The connection between flexible cables and LED PCBs in liquid crystal display devices is fragile, leading to frequent disconnections and soldering issues, which reduces the reliability of the LCD device due to weak connections and potential damage to circuit components.
Innovation Solution
Integrating a flexible printed circuit board (FPCB) with a bar-shaped portion for mounting LEDs and a leg portion that extends perpendicularly to connect to the LED driving circuit, providing a secure and rigid connection that minimizes disconnection risks and eliminates soldering problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flexible cable is used to connect the LED PCB to the LED driving circuit, then the device can be assembled with separate components, but the connection becomes fragile and prone to disconnection
Solution Approach 1:
The patent merges the LED mounting board and the flexible cable into a single integrated FPCB structure. The first portion of the FPCB serves as the LED mounting board while the second portion serves as the flexible cable, eliminating the separate flexible cable connection and its associated soldering joints that are prone to disconnection.
2Adaptability or versatility
If a flexible cable is bent to connect the LED PCB to the LED driving circuit, then connection flexibility is achieved, but soldering problems occur and disconnection risk increases
Solution Approach 1:
The FPCB integrates the rigid LED mounting portion and the flexible connecting portion into one continuous structure, eliminating the separate soldering joint between flexible cable and PCB. The integrated structure maintains flexibility where needed while ensuring reliable electrical connections throughout.
3Ease of repair
If separate flexible cable and LED PCB are used, then component replacement is easier, but the connection becomes weak and susceptible to damage
Solution Approach 1:
The patent creates an integrated FPCB where the LED mounting board and flexible cable are unified, eliminating weak soldering joints. The integrated structure distributes mechanical stress throughout the entire FPCB rather than concentrating it at connection points, thereby strengthening the overall assembly while maintaining repairability through the FPCB's inherent flexibility.
Data Source
AI summary
A liquid crystal display device includes a reflection plate; a light guide plate over the reflection plate; a light-emitting diode (LED) assembly including LEDs arranged along a side surface of the light guide plate, an LED flexible printed circuit board (FPCB) having LEDs mounted on its surface. The FPCB includes a bar and a leg portion extending from the body. The bar and the leg portion are integrated into a single body. The leg portion extends from the bar to a circuit for controlling the LEDs. A metallic bar is attached to bar of the LED FPCB to provide rigidity to the FPCB as well as cool the FPCB.